Science 8 Chemistry Unit

Matter

Anything that has mass and takes up space

Mass

the amount of matter in an object

Volume

The amount of space an object takes up

Units of Mass

kilograms (kg), gram, milligram

Units of Volume for a Soild

meter cube, cm cube, etc

Units of Volume for a Liquid

Liters, ml

Physical Properties

the characteristics of a substance that can be observed or measured without changing the chemical identity

Chemical Properties

The ability of matter to react with another substance to form one or more new substance

Some Examples of Physical Properties

Melting, Boiling, Melleability, Hardness, Solubility, Viscosity, Density, etc

Some Examples of Chemical Properties

Flammability, Combustibility, reactivity with acid, Reactivity with Oxygen, Lack of Reactivity, etc.

Melting/Boiling point

The temperature which as substance changes from solid to liquid/ changes from liquid to gas

meltability

describes how easily a substance can be hammered or bent into a differet shape

Solubility

A measure of how much substance can dissolve in a given solvent.

Viscosity

Describes how quickly a liquid substance flows in liquid form (the more dense a liquid, the more viscosity the have)

Density

quantity of mass un a certain volume of a specific material

Chemical properties can only be observed when a substance ________________ with another substance

chemically interacts

Combustibility

The chemical property of being able to burn and set on fire

The two types of changes are

Physical and chemical change

Physical Change

a change of matter from one form to another without a change in chemical properties

chemcial change

A change of matter that also produces 1 or more new products

4 main clues that a chemical change has occurred

A new substance or material is produced, Sound or light are given off (emission), Bubbles of gas are formed, a precipitate

The two tyope of matter data is

Qualitative and Quantitative data

Qualitative data

descriptive data

Quantitative data

numerical data

Mixtures

Can be seperated into parts physically

Pure Substances

elements and compounds

Elements (Pure substance)

Cannot be seperated or broken down physically or chemically

Compound (Pure Substance)

Can be broken down into 2 or more elements by chemical change but not physical change

what is the displacement method

Volume of water and solid together - the volume of water

Volumer

b x h x w

WHat should we use to measure volume?

Volumetric flasks

Where should we look to know the correct measurements when using a volumetric flask?

The meniscus

What is any form of matter that can flow?

fluid

What can be classified as a fluid becuase they dont have a fixed shape?

gas and liquid

Fluids do not mix because

they have different density levels

the units for density for fluids are

g/ml

the units for density for solids

g/cm3

What's the formula for calculating density?

m/v = d

What is buoyncy?

tendancy of floating in a fluid

formula for buoyancy

-DgV ( -Density x Gravity x Volume)

Gravity

9.81 m/ s2

What is made up of tiny particles in atoms and molecules?

Matter

4 states of matter

1. Solid
2. Liquid
3. Gas
4. Plasma

What has its own fixed shape and has a constant volume?

Solid

What takes the shape of its container and has a constant volume

Liquid

What takes the shape and volume of its container, and can be compressed

gas

What has a different electrical propertes than gases, but also dose not have a fixed volume or shape?

Plasma

kinetic energy

energy of motion

particles always moving produces

kinetic energy

Zero Kelvin

a point where all particles are at their lowest possible energy state and stops moving

Particles in a solid

are closely locked in position and can only vibrate, they attract each other too

Particles in a liquid

are free to move around one another by slipping and sliding but still touch

Particles in Gas

Move fast enough to overcome almost all of the attraction between them. The particles are far apart and move independently of one another

The more kinetic energy the particle has, the faster the move and the further apart they get!

Gas > Liquid > Solid

Change of states

when matter transform from one state to another

evaporation

Liquid to gas

Condensation

Gas to liquid

Freezing

liquid to solid

Melting

solid to liquid

deposition

gas to solid

sublimation

solid to gas

Temperature is the measure of

the average kinetic energy of particles in a substance

what happens when a matter is heated?

it gains energy and expands

What happens when a matter is cooled?

It contracts

Diffusion

is the movement of particles from an aread of high concentration to low concentration

John dalton (1766-1844)

was a school teacher and scholar

John dalton's hypothesis

1. All matter is made up of extremely small particles called atom.

2. Atoms connot be destroyed, created or divided

3. Atoms of a given element are identical in mass and properties.

JJ thompson

expanded on ideas about the electron

Ernest Rutherford

Expanded on the nucleus

Niels Bohr

expanded on ideas about energy levels

Plum Pudding

was the name JJ Thomson's model of the atom. A positively charged ball with negativity charged electrons embedded on it

Opposite attratcs

negative particles are attracted to the positive terminal

Repel

push away from each other

Nucleus

positively charged center of an atom

neutrons

particles with no charge in the nucleus

electrons

Negatively charged particles

protons

Positively charged particles

atomic theory

all matter is made up of particles (atoms)

atomic mass

total number of protons and neutrons

atomic number

number of protons

in. a neutral atoms

number of protons and electrons are the same

Dmitri Mendeleev

Father of the periodic table

elements

only have 1 type of atom

chemical symbols

are used to represent the elements, they consist of 1 or 2 letters, usually the first letter of their name, or from another language

Period

A horizontal row of elements in the periodic table, the # of their period, represents the # of energy shells they have

Families/ groups

Vertical columns on the periodic table, the groups 1,2, 13-18, has the # of electrons on thir outer shell based on their # of family (-10)

Group 1

alkali metals

Group 2

alkaline earth metals

group 17

Halogens

Group 18

noble gases, they are also the most stable elements, becuase they have a full outer shell

non metals, metalloids, metals

the 3 kinds of elements on the periodic table

maximum # of electrons in the 1 energy shell in a bohr diagram

2

maximum number of electrons in the second energy shell

8

maximum number of electrons in the third energy shell

18

maximum number of electrons in the 4th energy shell

32